1. Field of the Invention
This invention relates to bone saw guides for cutting a bone. More particularly, this invention relates to bone saw guides for angularly cutting a bone, in parallel cuts, allowing a bone segment to be removed and the complementary cut ends compressed together to shorten the bone.
2. Description of the Background Art
During bone shortening, it is often difficult to freehandedly cut a bone with a hand held saw, at precisely parallel cuts, so that a bone segment can be removed and the complementary ends of the bone compressed together at perfectly matching angles. Improper matching upon compression results in gaps in the compressed bone ends and therefore requires excessive healing time.
It can be readily appreciated that considerable skill is required to properly position the saw blade so that two parallel cuts are made through the bone at the desired angle and location along the longitudinal length of the bone.
Double-bladed bone saws have been developed to facilitate removal of bone segments. Basically, double-bladed bone saws comprise two parallel saw blades spaced apart from each other by a distance equal to the thickness of the bone segment to be removed and fixedly connected to a drive shaft. A motor rotates or oscillates the drive shaft causing simultaneous rotation or oscillation of the parallel blades. When freehandedly positioned against a bone, the blades simultaneously saw two parallel cuts in the bone. When cut through, the resulting bone segment is removed. Unfortunately, double-bladed saws must still be positioned freehandedly and are therefore subject to cutting the bone segment at a undesired angle or at an undesired location along the longitudinal length of the bone.
Therefore, it is an object of this invention to provide an apparatus which overcomes the aforementioned inadequacies of the prior art devices and provides an improvement which is a significant contribution to the
Another object of this invention is to provide a bone saw guide allowing perpendicular or angular cutting of a bone.
Another object of this invention is to provide a bone saw guide allowing the sawing of two parallel cuts through a bone so that a bone segment is removed from the bone.
Another object of this invention is to provide a bone saw guide for cutting a bone segment from a bone at precise angles so that the resulting bone ends are cut at complementary angles for precise matching, with no gaps, when the ends of the bone are compressed together.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.
SUMMARY OF THE INVENTION
This invention comprises a bone saw guide allowing the precise perpendicular or angular cutting of a bone with a conventional oscillating bone saw. More particularly, the bone saw guide of the invention comprises a plate for affixing to the bone by means of bone screws which are positioned through holes in the plate and then into previously drilled and tapped holes in the bone. The bone saw guide of the invention further comprises a blade guide portion including a substantially inverted U-shaped configuration having its depending legs spaced apart for straddling the bone therebetween when the plate is affixed to the bone. A plurality of blade slots are formed in the U-shaped blade guide portion to guide the oscillating blade of the conventional oscillating bone saw. The U-shaped blade guide portion is preferably angularly positioned relative to the plate so that cuts at the desired angle are made through the bone.
The bone saw guide of the invention further comprises a saw guide portion including a pair of upstanding guide arms extending upwardly from the plate in a spaced-apart configuration for receiving the cylindrical neck of the bone saw therebetween such that the neck and the bone are coplanar. A surface of each upstanding arms is angled relative to the plate at the same angle as the U-shaped guide portion so that the plane formed by the surface of the arms is parallel to the planes of the blade guides formed in the U-shaped blade portion. In this manner, the blade extending perpendicular from the cylindrical neck of the bone saw remains in alignment with at least one of the blade guides in the U-shaped blade portion during cutting.
An important feature of the bone saw guide of the invention is the precise cutting of the bone which minimizes the need for a steady and precise hand of the surgeon. Moreover, the spacing between the guides can be nonequidistant so different sized bone segments can be removed. For example, the bone saw guide of the invention having three blade guide slots with the second spaced from the first by three centimeters and a third spaced from the second by two centimeters, would allow the removal of a two, three or five centimeter segment of bone. Removal and repositioning of the plate of the bone saw guide to make two parallel cuts is therefore unnecessary.
Another important feature of the bone saw guide of the invention is the compatibility of using the bone saw guide of the invention first to cut and remove a bone segment and then use the bone compression and distraction device of my other invention (described in U.S. patent application, Ser. No. 254,158, filed Oct. 6, 1988, the disclosure of which is hereby incorporated by reference herein) to compress the ends of the bone together. Specifically, this compatibility can be achieved by positioning the fixation screws of the bone compression and distraction device in the same holes as the holes in the plate of the bone saw guide. This allows most of the holes drilled and tapped in the bone for the bone saw guide to be used by the screws needed for the plate of the bone distraction and compression device. Redrilling and tapping of additional holes in the bone is therefore minimized.
Another important feature is the possibility of now placing an interfragmentary screw across the oblique cut thus enhancing stability
The foregoing has outlined rather broadly the more pertinent and important features of the present invention in order that the detailed description of the invention that follows may be better understood so that the present contribution to the art can be more fully appreciated. Additional features of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.